116908

Appears in sequences

• Number of partitions of n-set with 2 block sizes.at n=8A088142
• a(n) = n*(n^3 - n + 2)/2.at n=22A101374
• Triangular array read by rows: T(n,k) is the number of set partitions of {1,2,...,n} that have exactly k distinct block sizes.at n=25A208437